Electrode holder



P. M. HALL ELECTRODE HOLDER Filed Feb. 29, 1944 m/ F 5 3 6. WWW/ @j Hm/ m Z/M April 24, 1945.

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Patented Apr.24,1945

UNITED STATES PATENT oFFlcl-z ELECTRODE HOLDER Preston M. Hall, Worcester, Mass.

Application February 29, 1944, Serial No. 524,411

(cl. 21e-4.)

4 Claims.

This invention relates to electrodes of the type commonly used in resistance spot-welding, and relates more particularly to the water cooling of such electrodes. It is common to make these electrodes hollow and to supply water to the interior thereof through a pipe extending into the electrode but spaced from the sides of an axial opening therein. Effective circulation of the cooling water is thus ensured.

It is the general object of my present invention to provide improved means for sealing the electrode in its holder and thus preventing the escape of water from the cooling system.

A further object is to provide sealing means So constructed that pressure applied to an electrode during a welding operation will more firmly seat and seal the electrode.

Preferred forms of the invention are shown in the drawing, in which Fig. 1 is a sectional front elevation of an electrode and holder which show a preferred form of my improved sealing construction;

Figs. 2 to 8 inclusive are similar views of modified constructions; and

Fig. 9 is a sectional front elevation showing a sealing construction particularly adapted to an offset electrode.

Referring particularly to Fig. 1, I have shown an electrode Ill secured in a holder I I by a slightly conical holder bushing I2 adapted to be forced into a corresponding slightly conical recess I4 in the holder II. The lower portion of the bushing I2 is slotted as indicated at I5, so that the bushing may be compressed as it is forced into the holder, with a resultant rm grip on the cylindrical outer surface of the electrode I0.

The conical recess I4 preferably has a cylindri- 'cal extension I6 terminating at a shoulder Il.

The lower end of the electrode I is preferably provided with rounded inner and outer edges and directly engages the shoulder I'l when the electrode is forced into the holder by the usual application of heavy welding pressure.

The electrode I0 is also provided with a cylindrical axial opening I8, and a pipe I9 conducts cooling water to the upper end of the electrode, the flow being indicated by arrows. The pipe I9 is substantially smaller than the opening I8, so that it is well spaced from the side walls thereof. Cooling water is thus permitted to enter the electrode through the pipe I9 and to return through the annular space between the pipe I9 and the side wall of the recess I8.

The seating of the electrode squarely against the shoulder I1 prevents leakage of water from the cooling system, `and the more pressure that is applied to the electrode, the more firmly the electrode is seatedand the more effective is th water seal.

The particular means shown in Fig. 1 for securing the electrode I0 in the holder I I is not claimed in this application, as it forms the subject matter of a copending application Serial No. 524,410, filed by me February 29, 1944. In the constructions shown in Figs. 2 to 9, the means for clamping lthe electrode in the holder is or may be the same as shown in Fig. 1 and no further explanation of this clamping means appears necessary.

Figs. 2 to 9.particularly disclose modified constructions by which a water-tight seal is provided between the electrode and the holder. In these figures, the pipe I9 is omitted for the sake of clearness, but it will be understood that such a pipe is to be used as above described.

In Fig. 2, the lower end of the electrode 20 is provided with a tapered conical end flange 2I which seats in a corresponding conical recess 22 in the holder 23. Furthermore, the conical recess 24 in the holder 23 is provided with a cylindrical extension 25 in which the lower end of the electrode 20 is a close sliding t. Consequently a double seal is provided, first'by engagement of the flange 2l with the wall of the .recess 22, and second by engagement of the lower end of the electrode 2D with the wall of the recess extension 25.

In the construction shown in Fig. 3, the slightly tapered recess 3D in the holder 3| is provided with a more abruptly tapered extension 32 which is engaged by the lower edge 33 of the electrode 34. Close engagement of the edge 33 with the conical wall of the recess extension 32 is facilitated by countersinking the lower end of the electrode, as indicated at 35, to provide a relatively thin and slightly yielding lower edge or corner.

In the construction shown in Fig. 4, the lower end of the electrode 40 seats against a shoulder 4I in the holder 42 and also fits snugly against the side wall of a cylindrical recess 43. This provides another construction in which a double seal is secured-first by engagement of the end of the electrode 40 against the shoulder 4 I, and secondby engagement of the periphery of the electrode against the side wall of the cylindrical recess 43.

In the construction shown in Fig. 5, an annular groove 50 is formed at the lower end of the conical recess 5I in the holder 52, and the annular lower end of the electrode 54 is rounded in cross section to correspond to the groove 50. The inner upper portion 55 of the grooved part of the holder is oil'set inwardly to avoid the very thin sharp edge which would otherwise form the inner boundary of the annular groove 50. The pipe which introduces the cooling water is to-clear the edge iii sufciently to avoid interference with the ow of water in the cooling system.

The construction shown in Fig. 6 is similar to that shown in Fig. 5, except that the annular groove d@ in the holder di is V-shaped in cross section. The [lower end of the electrode S2 engages the sides of the V-shaped groove at two separated points, thus again providing double sealing engagement. That portion d3 of the holder forming the inner boundary of the groove d@ is thickened and odset inwardly for the purpose described with reference to Fig. 5.

In Fig. 7, the holder lll has a more sharply inclined recess portion ii at the lower end of the conical recess l2. and this portion 'H terminates in a relatively at but slightly conical end surface or shoulder lil. The lower end of the electrode 'ld is rounded as to its outer corner and is seated apprommately at the point where the shoulder 'i3 meets the side wall of the recess portion ll.

In Fig. 8, the lower end of the electrode d@ is beveled, as indicated at 8l, and the lower end of the holder recess 32 has amore sharply tapered portion S3 fitting the beveled end 5i of the elec-V trode and terminating in a shoulder 8d against which also the electrode is seated. A further form of ydouble seal is thus provided.

In Fig. 9, the lower end 9B of the offset electrode 9i is threaded to engage a threaded portion 92 of the holder 93. The extreme lower end of the electrode is also beveled to seat against a conical shoulder 94 inthe holder 93. With this construction, an eiective seal is attained by ilrmly screwing the electrode 9| into the holder 98 and this operation is facilitated by the offset construction of the electrode.

In all of these constructions, it will be seen that the electrode may be quickly and easily removed from the holder by iirst loosening the holder bushing, as I2, and by then slightly tapping the electrode sidewise. This will easily loosen the electrode, even in such forms as shown in Figs. 2 and 4 in which the outer wall of the lower end of the electrode is snugly engaged. Obviously the electrode shown in Fig, 9 is readily loosened by unscrewing the same.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. A resistance welding electrode and holder in which coactingl surfaces of the electrode and holder engage to provide an edective liquid seal, said holder having a locking element and said electrode having substantial lateral `clearance with respect to the outer end of the holder to facilitate separation of the parts after said locking element is removed from locking position.

2. In a welding mechanism, an electrode, a holder, and a locking element to secure said electrode in said holder, said holder having a shoulder coacting with the inner end of the electrode to form a liquid seal between the electrode and holder, and said electrode also firmly engaging an inner side wall portion of said holder adjacent said shoulder but having substantial clearance with respect to the outer end portion of the holder after the locking element is removed from operative position.

3. In a welding mechanism, an electrode, a.

holder, and means to secure said electrode in said holder, the inner end of said electrode being rounded and convex, said holder having a shoulder coacting with the inner end of the electrode to form a liquid seal between the electrode and holder, and said shoulderhaving an annular concave groove to receive the rounded and convex inner end of said electrode.

4. In a welding mechanism, an electrode, a holder, and a locking device to secure said electrode in said holder, said holder having a. sealing surface engageable with the extreme inner end of said electrode to provide an effective liquid seal, and said electrode being of substantially less outside diameter than the inside of the outer end of said holder and being readily laterally displaceable relative to said holder after said locking device is removed from operative position,

. whereby said electrode may be easily removed from said holder.

PRESTON M. HALL. 

